UPPER MARLBORO, Md. (WJZ)– Was he defending his fellow officer? Or did he go too far? The second Prince George’s County police accused in the beating of a Maryland college student takes the stand.

Derek Valcourt has more on the dramatic testimony about why the officer says he hit John McKenna repeatedly with his baton.

Prosecutors say the officers went too far. The defense says they did what was necessary.

A judge has already ruled that this was not first-degree assault. The questions facing the jury are: Was it second-degree assault? And, was it misconduct in office?

McKenna and his college friends testified they were drinking to celebrate a University of Maryland basketball victory against Duke University when a they pushed through what police call a “rioting crowd.”

McKenna says he didn’t see riot police until he “skipped” right up on them. Cell phone video shows he immediately threw up his hands to surrender.

Officer Reginald Baker told jurors fear, adrenaline and training kicked in as he used his shield to push McKenna against the wall, then used a baton to knock him to the ground and strike him several more times to force him to open his clenched fists.

Officer James Harrison admitted he lied to investigators, denying his involvement for fear of his job. He testified Thursday morning he thought he saw McKenna hit the other officer and says he also believed the student had something in his hands which is why he says it was necessary to strike with his baton at least seven times.

But a prosecution policing expert told jurors the extra strikes while on the ground were an unjustified use of excessive force.

So far, jurors have only seen the wide shot of this beating.

They have not yet seen the enlarged, close-up version that WJZ has been showing its viewers and it’s not clear if they will ever get to see it.

Closing arguments and jury deliberations are set for Friday.

If convicted, the second-degree assault charge carries the possibility of up to 10 years in prison.